1. Field of the Invention
The present invention relates to a substrate processing method for cleaning substrates such as semiconductor wafers and then drying the substrates, and a substrate processing method therefor.
2. Background Art
When manufacturing a semiconductor device, a processing apparatus is used for cleaning, with the use of a chemical liquid, a semiconductor wafer (referred to as “wafer” below) held on a spin chuck. In a cleaning process performed by such an apparatus, a process liquid such as a deionized water is supplied to a wafer, and thereafter the wafer is rotated to remove liquid droplets therefrom due to the centrifugal force so as to dry the wafer.
Conventional methods for drying a wafer include methods for spraying a rotating wafer with an IPA (isopropyl alcohol) vapor, spraying a rotating wafer with atomized IPA, and supplying an IPA liquid to a rotating wafer. Another method for drying a wafer is, while supplying a deionized water to a wafer from a nozzle that radially moves outward from a rotational center of the wafer, to supply an IPA vapor or the like to the wafer at a position nearer to the rotational center than a position at which the deionized water is supplied (JP 11-233481A, and JP 2003-197590A).
However, when a wafer has a high hydrophobic property, the conventional processing method is disadvantageous in that particles generate on a surface of the wafer after it is subjected to a drying process. In particular, when a wafer has a larger diameter, it is difficult to restrain particles (such as stripe water marks generated by a precipitation of a chemical liquid or the like) from appearing near a peripheral portion of the wafer. A possible method for preventing the generation of such particles is to increase a supply amount of a drying fluid such as IPA. However, a larger cost is required for the fluid.